David A. Wood

An Embolic Deflection Device for Aortic Valve Interventions

OBJECTIVESnWe describe initial human experience with a novel cerebral embolic protection device.nnnBACKGROUNDnCerebral emboli are the major cause of procedural stroke during percutaneous aortic valve interventions.nnnMETHODSnWith right radial artery access, the embolic protection device is advanced into the aortic arch. Once deployed a porous membrane shields the brachiocephalic trunk and the left carotid artery deflecting emboli away from the cerebral circulation. Embolic material is not contained or removed by the device. The device was used in 4 patients (mean age 90 years) with severe aortic stenosis undergoing aortic balloon valvuloplasty (n = 1) or transcatheter aortic valve implantation (n = 3).nnnRESULTSnCorrect placement of the embolic protection device was achieved without difficulty in all patients. Continuous brachiocephalic and aortic pressure monitoring documented equal pressures without evidence of obstruction to cerebral perfusion. Additional procedural time due to the use of the device was 13 min (interquartile range: 12 to 16 min). There were no procedural complications. Pre-discharge cerebral magnetic resonance imaging found no new defects in any of 3 patients undergoing transcatheter aortic valve implantation and a new 5-mm acute cortical infarct in 1 asymptomatic patient after balloon valvuloplasty alone. No patient developed new neurological symptoms or clinical findings of stroke.nnnCONCLUSIONSnEmbolic protection during transcatheter aortic valve intervention seems feasible and might have the potential to reduce the risk of cerebral embolism and stroke.

Optical coherence tomography (OCT) evaluation of intermediate coronary lesions in patients with NSTEMI

INTRODUCTIONnCoronary angiography is commonly performed following non-ST segment elevation myocardial infarction (NSTEMI) to assess the need for revascularization. Some of these patients have myocardial infarction (MI) with no obstructive coronary atherosclerosis (MINOCA). Patients without severe obstructive lesions are usually treated conservatively. However, coronary angiography has known limitations in the assessment of lesion severity. We report our experience of using coronary Optical Coherence Tomography (OCT) in a series of patients without severe obstructive coronary lesions.nnnMETHODSn165 patients underwent coronary OCT at Vancouver General Hospital. NSTEMI was the clinical presentation in 70 patients and 26 had angiographically intermediate lesions with 40%-69% diameter stenosis. Prior to OCT image acquisition, intracoronary nitroglycerin 100-200μg was administered. Blood in the vessel was displaced using contrast media by manual injections.nnnRESULTSnOCT of the angiographically intermediate lesions showed larger minimal luminal area (MLA) than the angiographically severe lesions (MLA 3.3mm(2)±1.8mm(2) vs. 1.6mm(2)±0.6mm(2), p<0.001) and less severe % lumen area stenosis (54.2%±11.4% vs. 70.9%±6.8%, p=0.001). Plaque rupture or intracoronary thrombus was detected in 8/26 (31%) patients. PCI with stent deployment was performed in 16 patients (62%).nnnCONCLUSIONnIn stabilized patients with NSTEMI and angiographically intermediate disease, OCT examination confirmed the lack of severe anatomical stenosis in most patients. However, OCT also identified coronary lesions with unstable features. Further research is needed to help guide management of this subgroup of patients.

Fame Comes at a Cost: A Canadian Analysis of Procedural Costs in Use of Pressure Wire to Guide Multivessel Percutaneous Coronary Intervention

The FAME-study authors claimed that fractional flow reserve (FFR)-guided multivessel percutaneous coronary intervention (PCI) achieved superior clinical outcome and lower cost compared with no FFR. However, patients were intended to undergo multivessel PCI with drug eluting stents prior to randomization, which tipped the cost-analysis heavily in favour of FFR. We retrospectively evaluated 100 intermediate coronary lesions assessed by FFR, and determined whether to perform PCI based on visual angiographic assessment alone. We found that angiographic-guided treatment underestimated functional significance of intermediate lesions, resulting in fewer implanted stents compared to FFR guidance. This, in addition to the pressure wire cost, increased procedural expenditure 2- to 3-fold when using FFR-guidance.

Single coronary artery from the right aortic sinus of Valsalva with anomalous prepulmonic course of the left coronary artery.

Cardiac computed tomography allows for improved, noninvasive and accurate visualization of coronary artery anomalies. The case of a single coronary artery with origin from a single ostium in the right sinus of Valsalva with an anomalous course of the left coronary artery anterior to the pulmonary trunk is presented. The unusual distal reconstitution of a normal anatomical course at the junction of the mid and distal left anterior descending artery with occlusion of the proximal circumflex artery has not, to the authors knowledge, been previously described.

Adult Congenital Heart Disease Intervention: The Canadian Landscape

Once considered a childhood disease, the number of adults living with congenital heart disease (CHD) has now exceeded the number of pediatric patients. The landscape of percutaneous intervention for adult congenital heart disease (ACHD) has evolved over the past decade and has yet to be characterized in Canada. The aim of this study was to begin to understand the current infrastructure underlying ACHD interventions in Canada and to characterize the type and number of interventions being carried out across the country. A cross-sectional national survey was distributed by e-mail to all cardiac catheterization laboratory directors in 2015. All Canadian laboratories involved in ACHD interventions responded, encompassing 19 institutions spanning 69 cardiac catheterization laboratories. A total of 1451 percutaneous interventions were recorded. Nationwide, the most common simple ACHD interventions were for atrial septal defect and patent foramen ovale closures. The most common ACHD interventions of increased complexity were for coarctation stenting and transcatheter pulmonary valve implantation. There was a marked clustering of procedures in Ontario, Québec, British Columbia, and Alberta in keeping with Canadas population-density distribution. A total of 23 ACHD operators were identified, half of whom had ACHD-specific fellowship training. These data can be used as a starting point to inform the present state of affairs in the area and lay the groundwork for further work to assess resource allocation and human resource planning for the care of patients with ACHD in Canada.

Structural Heart Disease Intervention: The Canadian Landscape

Cardiovascular disease encompasses coronary artery disease and valvular heart disease, and the prevalence of both increases with age. Over the past decade, the landscape of interventional cardiology has evolved to encompass a new set of percutaneous procedures outside the coronary tree, including transcatheter aortic valve implantation, transcatheter mitral valve repair, and left atrial appendage occlusion. These interventions have sparked a new discipline within interventional cardiology referred to as structural heart disease (SHD) intervention. The access to and numbers of such procedures performed in Canada is currently unknown. This first of its kind survey of structural interventions provides insight into the landscape of SHD intervention in Canada and the challenges faced by cardiologists to deliver this important care.

Development of a Porcine Model of Coronary Stenosis Using Fully Percutaneous Techniques Suitable For Performing Cardiac Computed Tomography, CT-Perfusion Imaging and Fractional Flow Reserve

BACKGROUNDnThe aim of this study was to develop and describe percutaneous coronary angiographic techniques to create a porcine model of acute coronary stenosis with methacrylate plugs that can by assessed using fractional flow reserve (FFR), invasive coronary angiography and coronary computed tomographic (CT) perfusion imaging without introducing artefacts associated with surgical models.nnnMETHODSnFollowing animal care and institutional approval and using percutaneous coronary catheterisation techniques within an animal laboratory we introduced precision drilled methacrylate plugs into one of the three main coronary arteries of 10 experimental female pigs. Coronary pressure wire measurements were performed across the experimental stenosis for the calculation of FFR. Invasive coronary angiograms were obtained in stenosed arteries. Animals were transported to a dual source CT scanner (Siemens Healthcare, Forcheim, Germany) and CT perfusion imaging was performed.nnnRESULTSnTen (10) pigs were investigated with seven data sets obtained. Three (3) pigs expired prior to CT imaging secondary to pneumothorax, high grade coronary stenosis with induced cardiac arrhythmia and iatrogenic air embolism. Graded coronary stenosis was produced in six pigs in the LAD (2), LCX (2) and RCA (2) territories and one animal served as a control. Fractional flow reserve ranged from 0.21 to 0.91. Myocardial blood flow derived from dynamic CT perfusion imaging ranged from 3.5 to 136.7ml/100ml of tissue/minute. No artefacts from the deployment of the methacrylate plug, nor the plug itself, were identified.nnnCONCLUSIONSnFully percutaneous preparation of a pig model of acute coronary stenosis is feasible and provides subjects for imaging that are free of surgically induced artefact. This technique is substantially less expensive than surgically induced coronary stenosis and can be performed using standard catheterisation techniques with mobile imaging equipment. The technique is extendable to produce multivessel acute coronary stenosis and can be used for multimodality imaging.

Valve-in-Valve for Transcatheter Aortic Valve Replacement: Do Imaging Requirements Change?

Bioprosthetic surgical valves have shorter durability compared to mechanical devices and the risk of reoperation is often prohibitively high. Contemporary transcatheter valves have been, and will continue to be, successfully deployed within failing surgical prostheses utilizing a valve-in-valve technique. Detailed knowledge of the physical characteristics of the in situ surgical prosthesis is crucial for procedural success. Currently, the internal diameter of the surgical valve is the most important dimension used to size transcatheter valves. Unfortunately, there is significant variability in both labeling and reported dimensions between surgical valve manufacturers with no accepted gold standard. Multiple novel transcatheter valve systems are currently being developed for valve-in-valve applications that utilize a variety of innovative sizing criteria. Imaging plays a key role in all aspects of valve-in-valve implantation. Multidetector computed tomography (MDCT) can help size existing surgical prosthesis and is proving invaluable for next-generation device development and refinement. Although echocardiography provides important periprocedural guidance for radiolucent surgical prostheses, a detailed understanding of the radiopaque surgical landmarks is crucial for correct valve-in-valve positioning and thus successful implantation.

Catheterization Laboratory: X-Ray Equipment, Imaging Modalities and Programs, and Radiation Safety

Choosing the correct equipment and utilizing the most appropriate imaging modalities will not only improve the planning and performance of interventional cerebrovascular procedures, but also limit the radiation exposure for both the patient and laboratory personnel. Digital subtraction angiography remains the gold standard technique for assessing both lesion severity and plaque characteristics during cerebrovascular interventions. No single acquisition mode, however, will provide the best image quality and anatomical information in all situations. It is the operator’s responsibility to understand these differences and employ strategies to both maximize image quality and limit radiation exposure to ensure patient and staff safety.